The invention relates to a module for a modular conveyor mat, and to a conveyor mat built up from modules.
Such modules and mats are generally known and are used for conveying products. The modules are usually manufactured by molding, and are often manufactured from plastic material.
A customary module comprises a body part extending transversely to a conveying direction with a top for carrying products to be conveyed and a bottom for cooperation with a conveying track. The body part comprises at the front and rear as viewed in the conveying direction a series of hinge parts with contiguous receiving spaces alternately successive transversely to the conveying direction, so that hinge parts and receiving spaces can interdigitate with receiving spaces and hinge parts of similar modules successive in the conveying direction. Successive modules can then be hingedly coupled using hinge pins extending transversely to the conveying direction, reaching through hinge bores provided in the hinge parts.
In this manner, modules successive in the conveying direction can be joined to form a mat of a desired length. The mat is usually of endless design, so that it can be passed over a conveying track using return wheels. The width of the mat can then be varied by placing several modules next to each other transversely to the conveying direction and coupling them using continuous hinge pins. Rows of modules successive in the conveying direction may then be mutually staggered transversely to the conveying direction, so that continuous slits in the conveying direction between the modules of the mat can be avoided.
The bottom of the module may, near the middle as viewed in the conveying direction, be provided with a tooth chamber extending transversely to the conveying direction for receiving a tooth of a sprocket wheel. An advantage of such a configuration is that the sprocket wheel can guide the mat well. When the sprocket wheel is a driving wheel, furthermore, a relatively great force can be transferred. Such a module is known from NL1008600 in applicant's name, and is commercially obtainable as ‘1005 series mattop chain’ of Rexnord. In this module, the tooth chamber extends in the conveying direction over a distance greater than the width of one hinge part, and transversely to the conveying direction over a distance greater than the width of two hinge parts.
A disadvantage of such a tooth chamber, however, is that it is difficult, because of the space needed for the tooth chamber, to make the pitch of the mat small. In practice, the minimum pitch of the known modules with such a tooth chamber is at least 1 inch. Consequently, the module, when rounding a smaller sprocket wheel, can follow the circular form less well, so that the so-called polygon effect is relatively strong. In practice, during rounding, the polygon effect can lead to height variation and speed variation of the terminal end of the upper part of the conveyor mat. This can lead to problems especially with sprocket wheels having fewer than 10 teeth, given the above-mentioned minimum pitch of 1 inch.